0.6.12.46:

0.6.12.46:
	(got confused, thought GENCGC was excessively conservative,
		tried to fix it, then backed out)
	tweaked a lot of comments and some names in gencgc.c
	made GENESIS systematically propagate *SHEBANG-FEATURES*
		entries into #define's in sbcl.h. (This isn't currently
		used for anything -- I wrote it to support my confused
		make-GENCGC-less-conservative effort, which no longer
		exists. However, it seems harmless and could be useful
		e.g. for making C-level code depend on SB-SHOW, so I
		left it in.)